Method of adjusting write strategy of recordable disc

ABSTRACT

A method of adjusting a write strategy of a recordable disc comprises steps of: generating a test pattern on a power calibrating area of the recordable disc according to a first write strategy and a first write power; establishing a Pit-to-Land Inter-Symbol Interference table and a Land-to-Pit Inter-Symbol Interference table through measuring a plurality of Pits and Lands with different time lengths in the test pattern; and generating a second overdrive power by adjusting a first overdrive power of the first write strategy according to the Pit-to-Land Inter-Symbol Interference table and the Land-to-Pit Inter-Symbol Interference table.

FIELD OF THE INVENTION

The present invention relates to a method of adjusting a write strategyof a recordable disc, and more particularly to a method of adjusting awrite strategy of a recordable disc by using an ISI table (Inter-SymbolInterference table).

BACKGROUND OF THE INVENTION

Generally, there is a PCA (Power Calibrating Area) on a recordable disc.After the recordable disc is loaded into an optical disc burner for datawriting, an optical pickup of the optical disc burner is moved to thePCA for executing an OPC procedure (Optimal Power Calibratingprocedure). The OPC procedure is for generating an optimal write power,and then the optical disc burner can process the data writing to therecordable disc according to the optimal write power.

It is understood that data is recorded on spiral tracks of therecordable disc. In another word, the data must be encoded by a controlchip of the optical disc burner first, and then the optical disc burnercan drive a laser diode of the optical pickup to alternatively generatemarks and non-marks on the spiral tracks of the recordable discaccording to the signals of the encoded data. The non-marks recorded onthe recordable disc are defined as Lands, and the marks are defined asPits. Accordingly, when the OPC procedure is executed, the optical discburner can drive the optical pickup to generate a test patternconstructed by a plurality of Lands and Pits.

FIG. 1 is a diagram illustrating a write strategy of a DVD recordabledisc. Because the thermal diffusion may cause the actual length of thePit 10 greater than a designed value, for making the length of Pit 10(nT, n=3˜11) more accurate, the rising edge of a driving signal derivedby the laser diode is designed to delay by a front-edge delay time(t_(n1)), and the falling edge is designed to advance by a rear-edgeadvance time (t_(n2)). Moreover, an overdrive power (Po) is designed tosuperpose to a write power (Pw) at the initial stage and the later stageof the formation of the Pit 10.

As depicted in FIG. 1, the front-end overdrive power (Po), having afront-end overdrive time (t_(n3)), is superposed to the write power (Po)and initiated at the rising edge of the driving signal. The rear-endoverdrive power, having a rear-end overdrive time (t_(n4)), issuperposed to the write power (Po) and ended at the falling edge of thedriving signal. By using a 3T Pit as an example, t₃₁ is referred as thefront-edge delay time of the 3T Pit; t₃₂ is referred as the rear-edgeadvance time of the 3T Pit; t₃₃ is referred as the front-end overdrivetime of the 3T Pit; and t₃₄ is referred as the rear-end overdrive timeof the 3T Pit. Generally, the nT Pit 10 (n=3˜11) may have differentvalues of the front-edge delay time (t_(n1)), the rear-edge advance time(t_(n2)), the front-end overdrive time (t_(n3)), and the rear-endoverdrive time (t_(n4)), wherein these front-edge delay time (t_(n1)),the rear-edge advance time (t_(n2)), the front-end overdrive time(t_(n3)), and the rear-end overdrive time (t_(n4)) are together definedas a timing parameter set of a write strategy.

Generally, a recordable disc can be distinguished by reading themanufacture ID and the disc ID on the recordable disc. Because differentrecordable discs, released by different manufacturers or released by asame manufacturer but having different dyes on the data layer of therecordable disc, have different write strategies, therefore, all therecordable discs releases on the market must be collected and to beprocessed to find their corresponding parameters by using a verifyingprocedure. The verifying procedure is referred as a process of adjustingthe overdrive power (Po) and the timing parameter set according to eachmanufacture ID and disc ID, and then storing the adjusted overdrivepower (Po) and the adjusted timing parameter set to a read-only memory(ROM) of the optical disc burner. In another word, when a recordabledisc is loaded in the optical disc burner for data writing, the opticaldisc burner can obtain the overdrive power (Po) and the timing parameterset from the read-only memory (ROM) according to the manufacture ID andthe disc ID recorded on the track of the loaded recordable disc, andthen the optical disc burner defines a write strategy (with uncertainwrite power) of the recordable disc according to the overdrive power(Po) and the timing parameter set. The write strategy is then used onthe PCA for the OPC procedure. Alternatively, if the optical disc burnercannot find a matched manufacture ID or disc ID in the read-only memory(ROM) when the recordable disc is loaded, a standard overdrive power(Po) and a standard timing parameter set will be provided to the opticaldisc burner for defining a write strategy (with uncertain write power),and the write strategy is then used on the PCA for the OPC procedure.

The OPC procedure is to find the optimal write power (Pw) for combiningthe overdrive power (Po) and the timing parameter set to define thewrite strategy. In other words, the OPC procedure is for generating aplurality of test patterns on the PCA via providing a plurality ofdifferent write powers to the write strategy. The optical disc burnercan obtain an optimal write power through measuring these test patterns,and then defines a write strategy according to the optimal write power(Pw), the overdrive power (Po), and the timing parameter set. The writestrategy is then used by the optical disc burner for generating Pits andLands with different time lengths on the program area of the recordabledisc.

Conventionally, the overdrive powers (Po) and the timing parameter setsof write strategies for all the recordable discs released on the marketare adjusted and stored in the read-only memory (ROM) of the opticaldisc burner before the optical disc burner is published to the market;and the OPC procedure executed on the PCA is only used for generating anoptimal write power.

However, if a specific recordable disc, which is already released on themarket, requires some modifications, the overdrive power (Po) and thetiming parameter set used for the original recordable disc which isstored in the read-only memory (ROM) of the optical disc burner may notbe useful to the write strategy of the modified recordable disc. Ifusing an original overdrive power (Po) and an original timing parameterset to the modified recordable disc, a poor write quality or even a faildata reading may be resulted in. If using a standard overdrive power(Po) and a standard timing parameter set to a recordable disc when thedisc ID of the recordable disc cannot be contained in the read-onlymemory (ROM) of the optical disc burner, the poor write quality may bestill resulted in. Therefore, providing a dynamically adjusting methodfor an overdrive power (Po) and a timing parameter set of a recordabledisc is the main purpose of the present invention.

SUMMARY OF THE INVENTION

Therefore, the present invention discloses a method of adjusting a writestrategy of a recordable disc. In the present invention, an optimalwrite power and an optimal write strategy can be obtained through an OPCprocedure executed an optical disc burner.

Moreover, the present invention provides a method of adjusting a writestrategy of a recordable disc, comprising steps of: generating a testpattern on a power calibrating area of the recordable disc according toa first write strategy and a first write power; establishing aPit-to-Land Inter-Symbol Interference table and a Land-to-PitInter-Symbol Interference table through measuring a plurality of Pitsand Lands with different time lengths in the test pattern; andgenerating a second overdrive power by adjusting a first overdrive powerof the first write strategy according to the Pit-to-Land Inter-SymbolInterference table and the Land-to-Pit Inter-Symbol Interference table.

Moreover, the present invention provides a method of adjusting a writestrategy of a recordable disc, comprising steps of: generating aplurality of Pits and Lands with different time lengths on therecordable disc according to a first write strategy and a first writepower; establishing a Pit-to-Land Inter-Symbol Interference table and aLand-to-Pit Inter-Symbol Interference table by measuring the pluralityof Pits and Lands; and generating a second overdrive power by adjustinga first overdrive power of the first write strategy according to thePit-to-Land Inter-Symbol Interference table and the Land-to-PitInter-Symbol Interference table.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be fully understood from the followingdetailed description and preferred embodiment with reference to theaccompanying drawings in which:

FIG. 1 is a diagram illustrating a write strategy of a DVD recordabledisc;

FIGS. 2A and 2B are flow charts showing the method of adjusting a writestrategy of a recordable disc of the present invention;

FIG. 3A is a diagram illustrating an electric signal of a test pattern;

FIG. 3B is a diagram showing a Land-to-Pit ISI tables;

FIG. 3C is a diagram showing a Pit-to-Land ISI tables; and

FIG. 4 is a diagram showing a method of adjusting an overdrive power(Po) of a write strategy of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 2A and 2B are flow charts showing the method of adjusting a writestrategy of a recordable disc of the present invention. When arecordable disc is loaded in an optical disc burner, the optical discburner can define an initial write strategy according to an overdrivepower (Po) and a timing parameter set which are obtained from aread-only memory (ROM) according to a manufacture ID and a disc ID ofthe recordable disc, and the optical disc burner also provide an initialwrite power and a target β value (step S10). At this step, the opticaldisc burner may provide an initial write strategy defined from astandard overdrive power (Po) and a standard timing parameter set fromthe read-only memory (ROM) if the optical disc burner cannot find thematched disc ID of the loaded recordable disc in the read-only memory(ROM).

Afterward, the optical disc burner then uses the initial write strategyand the initial write power (Pw) to generate a test pattern on the PCA(step S15). The optical disc burner can obtain a β value throughmeasuring the test pattern. In another word, the β value is derived fromthe calculation of the symmetry analysis of the reflecting signal fromthe test pattern. If the difference between the calculated β value and atarget β value is greater than a first default value (step S20), thenthe method of the present invention moves to step S25 for furtheradjusting the write power (Pw). Alternatively, the method of the presentinvention moves to step S30 for comparing a jitter value of therecordable disc if the difference between the calculated β value and thetarget β value is within the first default value (step S20). In anembodiment of the present invention, the first default value is definedto ±1%. In another word, the write power (Pw) needs to be furtheradjusted if the difference between the calculated β value and the targetβ value is greater than ±1%; alternatively, the write power (Pw) isacceptable if the difference between the calculated β value and thetarget β value is located within ±1%. At step S25, the optical discburner will increase the write power (Pw) if the calculated β value isless than the target β value; alternatively, the optical disc burnerwill decrease the write power (Pw) if the calculated β value is greaterthan the target β value.

At step S30 of comparing the jitter value, firstly the optical discburner needs to measure a jitter value of the reflecting signal from thetest pattern. If the calculated jitter value is less than a seconddefault value (step S30), then the method of the present invention movesto step S33 for determining the current write strategy and the currentwrite power as an optimal write strategy and an optimal write power, andends the flow steps of adjusting the write strategy. In the embodimentof the present invention, the second default value is defined to 9%. Inanother word, the write power (Pw) and the write strategy are determinedand defined as the optimal write power and the optimal write strategy ifthe calculated jitter value is less than 9%; alternatively, the writepower (Pw) and the write strategy need to be further adjusted if thecalculated jitter value is greater than 9%, and the method of thepresent invention then moves to step S35.

At step S35, the write strategy, the write power (Pw), and thecalculated jitter value are temporarily stored in the read-only memory(ROM) of the optical disc burner. Then, the method of the presentinvention moves to step S40 for inspecting an ISI table (Inter-SymbolInterference table).

FIG. 3A is a diagram illustrating an electric signal of a test pattern.FIGS. 3B and 3C are diagrams showing the ISI tables. Generally, the testpattern generated on the PCA is constituted by a plurality of Pits andLands with different time lengths (3T˜11T). And for convenience, thetest pattern illustrated in FIG. 3A is only constituted by Pits andLands with time lengths 3T and 4T. After the test pattern is generatedon the PCA by the write power (Pw), an ISI table for indicating thedifference between the actual and the optimal positions of the Pits andLands can be established through analyzing the electric signal obtainedfrom the test pattern. As depicted in FIG. 3A, the test pattern issequentially constituted by a 3T Land, a 3T Pit, a 3T Land, a 3T Pit, a4T Land, a 4T Pit, a 4T Land, a 4T Pit . . . The ISI table can befurther divided into a Land-to-Pit ISI table and a Pit-to-Land ISI tableshown in FIG. 3B and FIG. 3C, respectively.

As depicted in FIG. 3A, the converting position is advanced 0.15T whenthe 3T Land is converted to the 3T Pit, therefore, the parameter a33 inthe Land-to-Pit ISI table of FIG. 3B is +0.15T. Afterward, theconverting position is advanced 0.2T when the 3T Pit is converted to the3T Land, therefore, the parameter b33 in the Pit-to-Land ISI table ofFIG. 3C is +0.2T, and the actual time length of the 3T Pit is 2.95T.Afterward, the converting position is advanced 0.2T when the 3T Land isconverted to the 3T Pit, therefore, the parameter a33 in the Land-to-PitISI table of FIG. 3B is updated to (+0.15T+0.2T)/2=+0.125T. Afterward,the converting position is no any delay or advance when the 3T Pit isconverted to the 4T Land, therefore, the parameter b34 in thePit-to-Land ISI table of FIG. 3C is 0T, and the actual time length ofthe 3T Pit is 3.2T. Afterward, the converting position is advanced 0.1Twhen the 4T Land is converted to the 4T Pit, therefore, the parametera44 in the Land-to-Pit ISI table of FIG. 3B is +0.1T. Afterward, theconverting position is delayed 0.15T when the 4T Pit is converted to the4T Land, therefore, the parameter b44 in the Pit-to-Land ISI table ofFIG. 3C is −0.15T, and the actual time length of the 4T Pit is 4.25T.Afterward, the converting position is delayed 0.05T when the 4T Land isconverted to the 4T Pit, therefore, the parameter a44 in the Land-to-PitISI table of FIG. 3 b is updated to (+0.1T−0.05T)/2=+0.025T, and theactual time length of the 4T Pit is 3.95T. Accordingly, theaveraged-actual time length of the 3T Pit illustrated in FIG. 3A is(2.95T+3.2T)/2=3.075T, and the averaged-actual time length of the 4T Pitillustrated in FIG. 3A is (4.25T+3.95T)/2=4.1T.

Because an actual test pattern includes a plurality of Pits and Landswith different time lengths (3T˜11T), therefore, a complete Land-to-PitISI table of FIG. 3B and a complete Pit-to-Land ISI table of FIG. 3C canbe established after all the Pits and Lands in the test pattern aremeasured and analyzed, so as the difference between the actual and theoptimal positions of Pits and Lands, for the following steps ofadjusting the write strategy, can be determined according to the ISItable.

At step S40 of FIG. 2, the parameters a33˜a1111 and b33˜b1111respectively in the Land-to-Pit ISI table of FIG. 3B and the Pit-to-LandISI table of FIG. 3C are inspected for determining if the ISI table isnormal or not. Generally, the ISI table is determined to normal if allthe parameters in the Land-to-Pit ISI table and the Pit-to-Land ISItable are less than a third default value; wherein the third defaultvalue is designed to T/12, T/16, or T/32 in the embodiment of thepresent invention. A normal ISI table at step S40 represents a limitspace for improving the write power (Pw) and the write strategy;therefore, the write power (Pw) and the write strategy are respectivelydetermined as the optimal write power and the optimal write strategy(step S33). Alternatively, the method of the present invention moves tostep S45 for determining a loop counting number if the ISI table isdetermined to not normal (step S40). The write strategy needs to befurther adjusted (step S55) if the loop counting number is less than adefault number.

If the ISI table is determined to not normal (step S40) but the loopcounting number is greater than the default number (step S45), acorresponding write power (Pw) and a corresponding write strategy of thesmallest jitter value will be respectively selected as the optimal writepower and the optimal write strategy if the time consuming of the OPCprocedure is concerned. In the embodiment of the present invention, thedefault number is designed to 12. In another word, the write power (Pw)and the write strategy, corresponding to the smallest jitter value amongthe 12 jitter value, are selected as the optimal write power and theoptimal write strategy (step S50) even the ISI table is still determinedto not normal but the loop counting number already reaches to 12.

If the ISI table is determined to not normal and the loop countingnumber is less than the default number, the method of the present thenmoves to step S55 for getting an updated write strategy throughadjusting the timing parameter set and the overdrive power (Po).

The following description is about the adjusting of the timing parameterset. The timing parameter set can be adjusted according to the ISItable, wherein the timing parameter set includes the front-edge delaytime (t_(n1)), the rear-edge advance time (t_(n2)), the front-endoverdrive time (t_(n3)), and the rear-end overdrive time (t_(n4)) withdifferent time lengths nT (n=3˜11). In the present invention, theaveraged front-edge error of a 3T Pit is

${\sum\limits_{n = 3}^{11}{a_{n\; 3}/9}};$the average front-edge error of a 4T Pit is

${\sum\limits_{n = 3}^{11}{a_{n\; 4}/9}};$and all the other averaged front-edge errors with different time lengthscan be obtained by the same way. Similarly, the averaged rear-edge errorof a 3T Pit is

${\sum\limits_{n = 3}^{11}{a_{3n}/9}};$the averaged rear-edge error of a 4T Pit is

${\sum\limits_{n = 3}^{11}{a_{4n}/9}};$and all the other averaged rear-edge errors with different time lengthscan be obtained by the same way. In the present invention, thefront-edge delay time (t₃₁) and the rear-edge advance time (t₃₂) of theupdated 3T Pit write strategy can be determined by the averagedfront-edge error, the averaged rear-edge error, and the averaged actualtime length of the 3T Pit; the front-edge delay time (t₄₁) and therear-edge advance time (t₄₂) of the updated 4T Pit write strategy can bedetermined by the averaged front-edge error, the averaged rear-edgeerror, and the averaged actual time length of the 4T Pit. According tothe same way, all the front-edge delay times and the rear-edge advancetimes of the updated nT Pit write strategy (n=5˜11) can be determined bythe averaged front-edge error, the averaged rear-edge error, and theaveraged actual time length of the nT Pit (n=5˜11). For example, if theaveraged front-edge error of a 3T Pit is +0.1T; the averaged rear-edgeerror of a 3T Pit is −0.2T; and the actual time length of a 3T Pit is3.3T; then the front-edge delay time (t₃₁) of the updated 3T Pit writestrategy can be adjusted to more delayed 0.1T than the originalfront-edge delay time, the rear-edge advance time (t₃₂) of the updated3T Pit write strategy can be adjusted to more advance 0.2T than theoriginal rear-edge advance time. Accordingly, the averaged actual timelength of the updated 3T Pit is closer to 3T, so as the averagedfront-edge error and the averaged rear-edge error of the updated 3T Pitare closer to 0. Similarly, all the other front-edge delay time (t_(n1))and the rear-edge advance time (t_(n2)) with different time lengths canbe adjusted according to the same way.

The following description is about the adjusting of the front-endoverdrive time (t_(n3)) and the rear-end overdrive time (t_(n4)) in thetiming parameter set. In the present invention, the front-end overdrivetime (t₃₃) and the rear-end overdrive time (t₃₄) of a 3T Pit can beupdated according to the averaged front-edge error of the 3T Pit

$\sum\limits_{n = 3}^{11}{a_{n\; 3}/9}$and the averaged rear-edge error of the 3T Pit

$\sum\limits_{n = 3}^{11}{a_{3n}/9.}$Similarly, the front-end overdrive time (t₄₃) and the rear-end overdrivetime (t₄₄) of a 4T Pit can be updated according to the averagedfront-edge error of the 4T Pit

$\sum\limits_{n = 3}^{11}{a_{n\; 4}/9}$and the averaged rear-edge error of the 4T Pit

$\sum\limits_{n = 3}^{11}{a_{4n}/9.}$According to the same way, all the front-end overdrive time and therear-end overdrive time of the nT Pit (n=5˜11) can be updated accordingto the averaged front-edge error and the averaged rear-edge error. Inthe embodiment of the present invention, the updated front-end overdrivetime (t₃₃) is the original front-end overdrive time adding to theaveraged front-edge error of the 3T Pit

${\sum\limits_{n = 3}^{11}{a_{n\; 3}/9}};$the updated rear-end overdrive time (t₃₄) is the original rear-endoverdrive time adding to the averaged front-edge error of the 3T Pit

$\sum\limits_{n = 3}^{11}{a_{3n}/9.}$For example, if the front-end overdrive time of a 3T Pit is 0.5T; therear-end overdrive time of the 3T Pit is 0.5T; the averaged front-edgeerror of the 3T Pit is +0.1T; and the averaged rear-edge error of the 3TPit is −0.1T; then the updated front-end overdrive time (t₃₃) of the 3TPit is 0.5T+0.1T=0.6T, and the updated rear-end overdrive time (t₃₄) ofthe 3T Pit is 0.5T−0.1T=0.4T. Similarly, all the front-end overdrivetimes and the rear-end overdrive times of Pits with different timelengths can be updated from the same way.

The following description is about the adjusting of the overdrive power(Po). Because the overdrive power (Po) plays a critical role of theaccuracy of a 3T Pit, all the front-edge errors and all the rear-edgeerrors of the 3T Pit obtained from the ISI table will be used forupdating the overdrive power (Po). FIG. 4 is a diagram showing a methodof adjusting an overdrive power (Po) of a write strategy of the presentinvention. After the Land-to-Pit ISI table of FIG. 3B and thePit-to-Land ISI table of FIG. 3C are established, the overdrive powercan be updated from the equation of:

$P_{o - {updated}} = {P_{o} + {P_{o} \cdot \left( {{\sum\limits_{n = 3}^{11}{a_{n\; 3} \cdot w_{n}}} + {\sum\limits_{n = 3}^{11}{b_{3n} \cdot w_{n}}}} \right) \cdot C_{{mapping}\; 1}}}$

The parameters a33˜a113 in the Land-to-Pit ISI table of FIG. 3Brepresent all the front-edge errors before the 3T Pit, and theparameters b33˜a311 in the Pit-to-Land ISI table of FIG. 3C representall the rear-edge errors after the 3T Pit. In the present invention, aspecific weight is applied to each front-edge error and each rear-edgeerror of the nT Land (n=3˜11) which are right before or right after the3T Pit. As depicted in FIG. 4, the weight (w3) of a front-edge error ofa 3T Land which is right before the 3T Pit is 24%, so as the weight (w3)of a rear-edge error of a 3T Land which is right after the 3T Pit is24%; the weight (w4) of a front-edge error of a 4T Land which is rightbefore the 3T Pit is 16%, so as the weight (w4) of a rear-edge error ofa 4T Land which is right after the 3T Pit is 16%; the weight (w5) of afront-edge error of a 5T Land which is right before the 3T Pit is 8%, soas the weight (w5) of a rear-edge error of a 5T Land which is rightafter the 3T Pit is 8%; the weight (w6) of a front-edge error of a 6TLand which is right before the 3T Pit is 2%, so as the weight (w6) of arear-edge error of a 6T Land which is right after the 3T Pit is 2%; theweights (w7˜w11) of front-edge errors of nT Land (n=7˜11) which areright before the 3T Pit is 0%, so as the weights (w7˜w11) of rear-edgeerrors of nT Land (n=7˜11) which are right after the 3T Pit is 0%. It isunderstood that the weights may be adjusted according to any specificrequirement, and the overdrive power obtained from the adjusted weightsis closer to optimal.

As depicted in FIG. 4, a first adjusting ratio, to be used for gettingthe updated overdrive power, is obtained by an adding value multipliedby a first mapping constant, wherein the adding value is a summary ofeach parameter (a33˜a113, b33˜b311) multiplied by each correspondingweight. For example, if the adding value is +0.15T and the first mappingconstant C_(mapping1) is designed to 1/10T, therefore, the updatedoverdrive power can be obtained from the equation of:P _(o-updated) =Po+(+0.15T×( 1/10T))Po=Po+(1.5%)Po

As depicted in FIG. 2, the method of the present invention then moves tostep S60 for updating the target β value after the write strategy isupdated through the updated timing parameter set and the updatedoverdrive power at step S55.

In the embodiment of the present invention, the target β value can beupdated through comparing the front-edge delay time (t₃₁) and therear-edge advance time (t₃₂) of the updated 3T Pit write strategy withthe front-edge delay time (t_(n1)) and the rear-edge advance time(t_(n2)) of any other updated nT Pits (n=4˜11). For example, if thefront-edge delay time (t₃₁) of the updated 3T Pit write strategy is0.6T; the rear-edge advance time (t₃₂) of the updated 3T Pit writestrategy is 0.4T; the front-edge delay time (t₄₁) of the updated 4T Pitwrite strategy is 0.5T; and the rear-edge advance time (t₄₂) of theupdated 4T Pit write strategy is 0.6T, then the updated target β valuemust be adjusted less than the original target β value due to therear-edge advance time (t₃₂) subtracting from the front-edge delay time(t₃₁) of the 3T Pit is greater than the rear-edge advance time (t₄₂)subtracting from the front-edge delay time (t₁₄) of the 4T Pit([0.6T−0.4T]>[0.5T−0.6T]). A second adjusting ratio, to be used forgetting the updated target βvalue, can be obtained from a subtractingvalue multiplied to a second mapping constant, wherein the subtractingvalue is the difference (0.3T) between the rear-edge advance time (t₃₂)subtracting from the front-edge delay time (t₃₁) and the rear-edgeadvance time (t₄₂) subtracting from the front-edge delay time (t₄₁). Inthe embodiment of the present invention, the second mapping constantC_(mapping2) is designed to 1/20T. Therefore, the second adjusting ratiois obtained from the equation of 0.3T× 1/20T=0.015=1.5%, in anotherword, the updated target β value is needed to be adjusted smaller 1.5%than the original target β value. Alternatively, the updated target βvalue is need to be adjusted greater than the original target β value ifthe rear-edge advance time (t₃₂) subtracting from the front-edge delaytime (t₃₁) is less than the rear-edge advance time (t₄₂) subtractingfrom the front-edge delay time (t₄₁).

As depicted in FIG. 2, after the overdrive power (Po), the timingparameter set are updated at step S55, and the target β value is updatedat step S60, the method of the present invention then moves back to stepS15 for generating a test pattern on the PCA.

In the embodiment of the present invention, both the optimal write powerand the optimal write strategy can be obtained by the OPC procedureexecuted on the PCA. Therefore, the data can be recorded on therecordable disc by the optical disc burner according to the optimalwrite power and the optimal write strategy, so as the write quality ofthe recordable disc can be improved efficiently. Moreover, it isunderstood that the OPC procedure is not limit to execute on the PCA.The OPC procedure can be executed on other area (e.g., program area) forthe method of adjusting the write strategy of the present invention.

While the invention has been described with reference to the preferredembodiments, the description is not intended to be construed in alimiting sense. It is therefore contemplated that the appended claimswill cover any such modifications or embodiments as may fall within thescope of the invention defined by the following claims and theirequivalents.

1. A method of adjusting a write strategy of a recordable disc,comprising steps of: generating a test pattern on a power calibratingarea of the recordable disc according to a first write strategy and afirst write power; establishing a Pit-to-Land Inter-Symbol Interferencetable and a Land-to-Pit Inter-Symbol Interference table throughmeasuring a plurality of Pits and Lands with different time lengths inthe test pattern, wherein the Land-to-Pit Inter-Symbol Interferencetable at least includes a plural of front-edge errors from a plural ofLands with different time lengths to a Pit with a time length of 3T andthe Pit-to-Land Inter-Symbol Interference table at least includes aplural of rear-edge errors from a Pit with a time length of 3T to aplural of Lands with a different time lengths; providing a weight toeach front-edge error and each rear-edge error; determining an adjustingratio of a first overdrive power by multiplying a mapping constant by asummary of all the front-edge errors and the rear-edge errors with theweights; and generating a second overdrive power by adjusting the firstoverdrive power of the first write strategy according to the adjustingratio.
 2. The method according to claim 1, wherein the second overdrivepower is the first overdrive power adding to a value of the adjust ratiomultiplied by the first overdrive power.
 3. A method of adjusting awrite strategy of a recordable disc, comprising steps of: generating aplurality of Pits and Lands with different time lengths on therecordable disc according to a first write strategy and a first writepower; establishing a Pit-to-Land Inter-Symbol Interference table and aLand-to-Pit Inter-Symbol Interference table by measuring the pluralityof Pits and Lands, wherein the Land-to-Pit Inter-Symbol Interferencetable at least includes a plural of front-edge errors from a plural ofLands with different time lengths to a Pit with a time length of 3T, andthe Pit-to-Land Inter-Symbol Interference table at least includes aplural of rear-edge errors from a Pit with a time length of 3T to aplural of Lands with a different time lengths; providing a weight toeach front-edge error and each rear-edge error; determining an adjustingratio of a first overdrive power by multiplying a mapping constant by asummary of all the front-edge errors and the rear-edge errors with theweights; and generating a second overdrive power by adjusting the firstoverdrive power of the first write strategy according to the adjustingratio.
 4. The method according to claim 3, wherein the second overdrivepower is the first overdrive power adding to a value of the adjust ratiomultiplied by the first overdrive power.